The invention relates to a ring binder mechanism having a resilient mechanism cover, which can be located on a book-shaped cover, and two ring-rail or ring-coil members which are articulately connected in opposite directions and carry ring portions forming rings jointly in pairs, and which are resiliently supported in the mechanism cover and can be transferred into the open or closed position by means of at least one actuating member.
In a ring binder mechanism of this type known from U.S. Pat. No. 3,884,586, the actuating members provided at both ends of the mechanism cover are each formed by levers pivotable about a horizontal axis extending transversely to the longitudinal direction of the mechanism cover, which levers engage in recesses in the ring rail members and are located in these. When the ring portions are in the closed position, the handle portions of the levers have a position directed obliquely upwards out of which they can be pivoted still further into a vertical position locking the ring portions against accidental opening. Limits are imposed on the dimensions of the levers in view of the written matter to be filed and very considerable finger pressure is needed to actuate the mechanism because of unfavourable angle and lever-arm conditions. Operation is additionally made more difficult by the fact that when the ring portions are in the closed position with written matter inserted, the handle portions of the levers are only accessible with difficulty.